Virtual private network (VPN)
A Virtual Private Network (VPN) is a technology that creates a secure, virtual connection to a private network over a public network, primarily the internet. It allows authorized users to send and receive data and access network resources as if they were directly connected to a private network. VPNs are commonly utilized by businesses to connect different office locations or to enable remote employees to securely access company networks. Additionally, they can facilitate the secure connection of multiple home networks for personal use.
The development of VPN technology began with the point-to-point tunneling protocol (PPTP), coauthored by Microsoft engineer Gurdeep Singh Pall in 1996, which provided a way for users to establish a secure connection without the slow speeds of dial-up. VPNs offer several advantages, including enhanced security through data encryption, reliability, and scalability. However, there are security risks, as all devices connected to a VPN become part of the same internal network, potentially exposing the entire network if one device is compromised.
There are two main types of VPN connections: remote-access VPNs, which allow individual users to connect to a private network from anywhere with internet access, and site-to-site VPNs, which connect entire private networks without requiring client software. As cloud infrastructure has grown in popularity, more companies have adopted cloud VPNs, enabling secure access to cloud-based resources.
On this Page
Subject Terms
Virtual private network (VPN)
A virtual private network (VPN) forms a secure, virtual connection to a private network through a public network, most typically the internet. A VPN connection enables authorized users to send and receive data and to access networked resources as if they were directly plugged into private network servers. VPN connections are most often used to connect a company’s disparate office locations or to enable employees to access a company’s private network from home or other remote locations, but VPNs can also be used to securely connect multiple home networks for personal use.
Overview
Microsoft software engineer Gurdeep Singh Pall coauthored the first VPN protocol, point-to-point tunneling protocol (PPTP), in 1996. PPTP enables a computer to establish a secure connection, called a “tunnel,” to a remote server. Pall created PPTP to enable his coworkers to work effectively and securely from home or other remote locations without the need to connect to the company’s servers through slow dial-up connections. Instead, with PPTP, users could log on to Microsoft’s servers using high-speed internet.
Prior to the development of VPNs, networked computers were connected through leased lines, which were often slow, expensive, and difficult to expand. Before VPN technology was widely adopted, businesses typically rented leased lines from telecommunications companies to create wide-area networks that connected various office locations. However, leased lines were extremely expensive, with costs rising as the distance between two connected locations increased.
A VPN enables a private network to be extended across a public network, such as the internet. VPNs offer the benefits of security, reliability, and scalability, meaning that they are easily extended and modified. VPNs encrypt and encapsulate outgoing data to protect it from public view. However, security concerns remain when connecting two private networks through a public resource. A disadvantage of VPN is that all computers connected to the VPN become part of the internal network. If one machine connected to the VPN is hacked, the hacker will then be able to access the VPN to attack the intranet.
There have traditionally been two primary types of VPN connections, remote-access and site-to-site VPNs. A remote-access VPN enables individual users to connect to a private network from a remote location using any computer with internet access. To form a remote-access VPN, a network-access service (NAS), which may be a server or a software application, prompts the user to enter valid credentials before accessing the VPN, and client software establishes and maintains the connection to the VPN. Site-to-site VPNs, which connect entire private networks together, do not require client software. Site-to-site connections are either intranet-based VPNs, which forms a single private internal network, or extranet-based VPNs, which forms a secure, shared network while preventing shared access to separate intranets. Intranet-based VPNs are useful for connecting a branch office network to a company headquarters network, while extranet-based VPNs are used to connect companies with their partners, vendors, and customers without granting full access to the company’s internal network.
By the 2020s, an increasing number of companies had begun to host their infrastructure in the cloud, a global network of servers accessed through the internet. In response, more cloud VPNs, or VPN as a service, were developed and put into use. This allowed secure remote access to cloud-based infrastructure.
Bibliography
Bidgoli, Hossein, ed. “Infrastructure for the Internet, Computer Networks, and Secure Information Transfer.” Handbook of Information Security, Threats, Vulnerabilities, Prevention, Detection, and Management. Vol. 3, Wiley, 2006, pp. 337–808.
"Device Security Guidance: Virtual Private Networks (VPNs)." National Cyber Security Centre, www.ncsc.gov.uk/collection/device-security-guidance/infrastructure/virtual-private-networks. Accessed 2 Oct. 2024.
Geier, Eric. “How (and Why) to Set Up a VPN Today.” PC World, 19 Mar. 2013, www.pcworld.com/article/457163/how-and-why-to-set-up-a-vpn-today.html. Accessed 2 Oct. 2024.
Geier, Eric. “Set Up a Safe Virtual Private Network.” PC World, June 2013, pp. 29–30.
“How Does a VPN Work?" Cisco, www.cisco.com/c/en/us/solutions/small-business/resource-center/security/how-does-a-vpn-work.html. Accessed 2 Oct. 2024.
Mairs, John. VPNs: A Beginner’s Guide. McGraw-Hill, 2002.
Raghunath, Satish. “Resource Management for Virtual Private Networks.” IEEE Communications Magazine, 45, no. 4, 2007, pp. 38–44.
Rosenberg, Eric, and James Uttaro. “Scaling Virtual Private Networks.” Recent Patents on Engineering, vol. 1, no. 3, 2007, pp. 206–13.
"What Is a Cloud VPN? Cloud-Based Remote Access VPNs Explained." Palo Alto Networks, www.paloaltonetworks.com/cyberpedia/what-is-a-cloud-vpn. Accessed 2 Oct. 2024.
"What Is a VPN?" Microsoft, azure.microsoft.com/en-us/resources/cloud-computing-dictionary/what-is-vpn. Accessed 2 Oct. 2024.
Zwicky, Elizabeth D., et al. Building Internet Firewalls. 2nd ed., O’Reilly, 2000.